It is customary that certain types of heavy machines such as excavators, forestry machines and wood treatment machines have a tool arm, whereupon one or more appliances/tools can be attached by means of a so called quick coupler. Thereby suitable appliances/tools can be swiftly locked to or be made free from the tool arm. It is customary that such a quick coupler can have a locked position, wherein at least one appliance/tool is locked to the tool arm, and an unlocked position wherein the appliance/tool is made free from the tool arm.
FIG. 1 shows a tool arm/working arm or a shaft 2, in this example of an excavator, wherein said working arm 2 carries an upper fastening portion 10A for the mounting of a manoeuvring apparatus 15 which in the shown example includes a combined rotation device and tilting device. The manoeuvring apparatus 15 includes an upper fastening portion 10B for fastening co-operation with the upper fastening portion 10A of the working arm 2. The manoeuvring apparatus 15 further carries a lower fastening portion 16A for fastening co-operation with a fastening portion 16B of an appliance which in the illustrated case is comprised of a digging bucket 5 but can be any another suitable appliance or tool.
The manoeuvring apparatus 15 is an example of an intermediate part 20 being mounted between the working arm 2 and the appliance 5 in order to increase the movement ability of the appliance 5. It should be understood that this series-connected intermediate part 20 can be constructed in many different ways and exhibit a number of different additional characteristics. The intermediate part 20 can of course be left out where no extra characteristics are desired and then direct connection takes place between the parts 10A and 16B.
As is illustrated in the figures, the fastening portion 10B of the intermediate part 20 includes two parallel fastening pins 30, 31 which are arranged to fit into corresponding recesses 40, 41 being provided in the fastening portion 10A of the working arm 2. In a corresponding manner, the fastening portions 16B of the appliance 5 exhibits two parallel fastening pins 30, 31 which are arranged in a corresponding manner as the previously mentioned fastening pins 30, 31. The fastening pins 30, 31 fit into the corresponding recesses 40, 41 being arranged in the fastening portion 16A.
From the above it is to be understood that the appliance 5 can be directly connected without any intermediate part 20, through direct engagement between the fastening portions 10A and 16B. FIGS. 3-5 illustrate the construction of a co-operating pair of fastening portions which for example could be 10A+10B, 16A-16B or 10A-16B.
FIGS. 3-5 show a connecting procedure between for example an upper fastening portion 10A of a working arm 2 and lower fastening portion 16B of for example an appliance 5. The fastening portion 10A includes two first recesses 41 which come into engagement with (the second) fastening pin 31 and at the same time allow a swing movement between the portions 10A and 16B around the fastening pin 31. A connecting operation (or locking operation) is normally initiated through manoeuvring into said engagement (see FIG. 3). Thereupon a swing manoeuvre takes place with the fastening pin 31 as swing axis such that the (first) fastening pin 30 reaches the bottom in two second recesses 40 of the fastening portion 10A. Thereupon locking together of the fastening portions 10A and 10B takes place by bringing forward a locking wedge 50 from an initial position according to FIG. 4 to a locking position according to FIG. 5. Manoeuvring of the wedge is normally performed by a double-acting hydraulic cylinder 51.
FIG. 5 shows that the locking wedge 50 fixes the fastening pin 30 in the recesses 40 at the same time as the fastening pin 31 is fixed in the recesses 41. The above described results in a very secure locking, provided that the locking wedge 50 ends up in correct contact with the fastening pin 30, which is unfortunately not always the case. This could result in that the appliance drops off, whereby a falling appliance risks causing personal injuries as well as material damages. When disconnecting an appliance, the above described connecting procedure is reversed, wherein the locking wedge 50 is re-manoeuvred to its initial position according to FIG. 4.
In order for an operator/vehicle driver visually to be able to establish that the connection has been successful, it is common to use a so called indicator rod 60 which is arranged to follow the movement of the locking wedge 50, whereby a certain protrusion 61 of the rod verifies adequate locking of the appliance. Said visual inspection is sometimes difficult to perform from the driver's cabin.